The present invention relates to fluidized bed apparatus and methods for operating the same.
Apparatus of this type is conventionally used for the purpose of gasifying particles such as petroleum coke particles into a fuel gas such as methane gas. When utilizing a fluidized bed apparatus for such purposes, one of the problems encountered is in connection with attrition of the particles. In other words, the movement of the particles about in the fluidized bed in which they are suspended is sufficiently violent to cause the particles to impact each other in a highly undesirable manner creating fines which undesirably flow out of the reactor vessel, together with the generated fuel gas. As pointed out above, in the case of petroleum coke particles, this gas will be essentially a methane type of low BTU fuel gas. Thus, because of the attrition occurring in conventional fluidized beds it is unavoidable that an undesirably large amount of fines will issue from the reactor vessel with the gas achieved from the particles such as petroleum coke particles.
Moreover, in conventional fluidized bed apparatus there is a problem in connection with achieving a uniform distribution of the fluidizing gas over the grid as well as in connection with achieving proper support for the grid and maintenance of the grid at a temperature low enough to assure a long operating life. Furthermore, conventional nozzles tend undesirably to become clogged and replacement of the nozzles very often creates great difficulties.